Battery removal, torn black outer material - dangerous?

I'm changing the rear, aluminium casing on an iPad 2 which obviously involves prying up the battery from the large amount of adhesive that it's stuck down with.

I did this as carefully as possible, but a small amount of the black material or 'film', that covers the battery was left behind on the old casing adhesive.

This has exposed a small area of the battery (I can see a silver layer underneath) and the battery also now has a 'chemical' or 'solvent' smell to it.

The three cells have also bent very slightly during the removal process (it seems almost impossible to me to get them out perfectly flat)

Is this battery still safe to re-use or do I need to buy a replacement?

If I do need to replace it, is it safe to store inside my house in the mean time or is there any risk of fire/explosion?

Thanks in advance for any advice.